PLANAR TYPE SEMICONDUCTOR DEVICE WITH A HIGH BREAKDOWN VOLTAGE

摘要

A planar type semiconductor device having a high breakdown voltage, including a diffusion region of a P type formed in a semiconductor layer of an N type, a guard ring region of the P type formed in the semiconductor layer and surrounding the diffusion layer, and an insulating film covering the surface of the semiconductor layer between the diffusion and guard ring region. A field plate is provided which is kept at a potential equal to that of the diffusion region. The field plate covers the entire surface of that portion of the insulating film which is between the diffusion and guard ring regions.